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Unformatted text preview: Chapter 1: Biology and the Tree of Life cell theory : all organism are made of cells and all cells come from preexisting cells theory of evolution by natural selection : species have changed through time and all species are related to one another through common ancestry theory : an explanation for a very general class of phenomena or observations 1. The Cell Theory Chapter 24: Evolution by Natural Selection special creation : the theory that all species were created independently by god, and that species are immutable (incapable) of change and have been unchanged since the moment of their creation Darwin asserted that the Earth was ancient and that species change over time scientific theories have 2 components: pattern + process pattern: process 24.1 The Evolution of Evolutionary Thought revolution : overturn things; replace an existing entity with something new and often radically different scientific revolution : overturns an existing idea and replaces it with another, radically different, idea Plato claimed that every organism was an example of a perfect essence, or type, created by god, and that these types were unchanging compared deviations to shadows Aristotle ordered organisms into chain of being chain of being : species are organized into a sequence based on increased size and complexity, with humans at the top typological thinking : based on the idea that species are unchanging types and that variations within species are unimportant or misleading Jean-Baptiste de Lamarck proposed that species are not static and have changed through time first to propose a formal theory of evolution o pattern based on chain of being; simple organisms at base of change by spontaneous generation and evolve by moving up the chain over time o progressive: always producing larger and more complex (better) species o species change through time via acquired characters ; individuals change as they develop in response to challenges posed by the environment and pass on these phenotypic characteristics to offspring (i.e. giraffes have long necks because they stretch them to feed from high treetops) evolution : the idea that species change through time Darwin + Wallace proposed that evolution isnt linear and emphasized that variation among individuals in populations is responsible for change through time variation among individuals = key to understanding nature of species o evolution occurs because traits among individuals in a population vary, and individuals with certain traits leave more offspring than others population : individuals of the same species living in the same area at the same time 24.2 The Pattern of Evolution: Have Species Changed through Time?...
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